USC came to the Coliseum Saturday as a team that needed to leave with a win, and on that front, the Trojans accomplished their mission.

But even in victory, questions lingered about USC's discipline after a flag-filled 27-6 win against an overmatched Washington State.

"I look at it like it's great to win. It's fun to win at Coliseum; we love doing it," USC head coach Pete Carroll said. "But we've got work to do. This was not the satisfying win that we would have liked to have had."

Take the first quarter, when USC did almost everything right. Matt Barkley passed for 136 yards and two long scores. Joe McKnight gashed the defense at will, seemingly, on his way to a great start. The Trojans even recovered an onside kick.

But even after putting up 20 points in the game's first 15 minutes, the mistakes were as glaring as the yellow flags littering the Coliseum's green grass.

In the first quarter, USC was flagged for seven penalties, giving Washington State 75 yards of field position.

"They're penalties," guard Alex Parsons said. "It's one of those things. We just have to be disciplined and get our hands inside. It's from not being disciplined."

After the game, Carroll said he would review the film and most likely challenge half of the calls. USC got flagged 13 times Saturday for 115 yards.

While penalties have plagued USC in each of its three opening games, USC seemed to shake the stench of conservative play calling that has lingered in Trojans' wins and losses.

Barkley hooked up with Stanley Havili for a 33-yard gain, found Brice Butler for a 29-yard score and, on the first play after the onside kick, Barkley found Damian Williams streaking for a 57-yard touchdown.

"We knew we could stretch them vertically," Barkley said. "We were going to try to throw the ball deep. We hit what we could when it was there."

Barkley finished the game 13-of-22 for 247 yards and two touchdowns.

But while the vertical passing game improved, there are still some unresolved issues on special teams. USC missed an extra point and a field goal, and the Trojans muffed a punt. However, Jacob Harfman, starting for the first time, averaged 46.3 yards on his three punts. He also recovered his own onside kick.

Despite the penalties, the special teams errors and a rare Williams fumble that kept things relatively close, USC still managed to keep control of the game thanks to a merciless defense.

"It was not a tough game for the defense," Carroll said. "We were in control, and we were on top of everything they tried to do. With eight sacks, it was a pretty big night."

Perry, who redshirted last season, got there twice and now leads USC with 6.0 sacks this season.

"(Sitting out) made me hungrier. It made me stronger," Perry said. "During that whole year, I got to learn everything."

The defense even recovered a pair of fumbles in the second half. Stafon Johnson took advantage of the good field position to rush for a six-yard touchdown after Devon Kennard's fumble recovery. But after the next Cougar turnover, USC's offense failed to score after going for it on fourth-and-goal from the 2.

USC struggled in a short-yardage situation in the first half as well, electing to go for the touchdown on fourth-and-goal from the 2-yard line. Barkley rolled out and fired the ball at Rhett Ellison, but the pass fell to the ground after hitting his hands.

Washington State had a great chance to score late, but Josh Pinkard stepped in the path of Tuel's throw and intercepted the pass right in front of the goal line. The Cougars, however, did add a late touchdown after an Aaron Corp fumble.

In the winning effort, USC did lose defensive tackle Hebron Fangupo to a broken left ankle. Also, USC's leading tackler on the night, Jordan Campbell (eight tackles) left early in the third quarter with a left ankle sprain.

With a trip to Cal coming next week, Carroll said he knows his team has to improve on some key areas like taking care of the football, reducing penalties and converting on third and fourth-down situations.

"We have to get right. We have to keep working on it..." Carroll said. "There are plenty of things to win with, but we certainly can give a game away."